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Phenotypes Associated with This Genotype
Genotype
MGI:2684122
Allelic
Composition
Sp8tm1Smb/Sp8tm1Smb
Genetic
Background
involves: 129S1/Sv * 129X1/SvJ
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Sp8tm1Smb mutation (0 available); any Sp8 mutation (29 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
embryo
• impaired posterior neuropore closure
• impaired anterior neuropore closure (J:86196)
• at E9.5, embryos show failure of anterior neuropore closure (J:200761)
• observed in all fetuses

nervous system
• impaired posterior neuropore closure
• impaired anterior neuropore closure (J:86196)
• at E9.5, embryos show failure of anterior neuropore closure (J:200761)
• observed in all fetuses
• observed in nearly all fetuses (J:86196)
• enecephalocoeles were not observed (J:86196)
• at E18.5, a large hole is noted between the residual frontal and parietal bones, where exencephalic brain is exposed (J:200761)
• after embryonic exposure to 150 mg/kg cyclopamine (an SHH signaling inhibitor), approximately one third of cyclopamine-treated embryos show a partial rescue of the exencephaly phenotype (J:200761)

limbs/digits/tail
• the radius and distal bones were absent
• truncated ulna
• normal formation of the humerus
• distally truncated
• lacked structures distal to femur
• complete absence of the tail

skeleton
• at E18.5, the frontal bone is absent or reduced in size and misshapen
• at E18.5
• at E18.5, the interparietal bone is absent or reduced in size and misshapen
• at E18.5, the supraoccipital bone is reduced in size and misshapen
• at E18.5, the parietal bone is absent or reduced in size and misshapen
• at E18.5, the maxilla is reduced in size and misshapen
• at E18.5, the premaxilla is reduced in size and misshapen
• distally truncated
• abnormal and disorganized lumbar vertebrae

craniofacial
• at E18.5, the frontal bone is absent or reduced in size and misshapen
• at E18.5
• at E18.5, the interparietal bone is absent or reduced in size and misshapen
• at E18.5, the supraoccipital bone is reduced in size and misshapen
• at E18.5, the parietal bone is absent or reduced in size and misshapen
• at E18.5, the maxilla is reduced in size and misshapen
• at E18.5, the premaxilla is reduced in size and misshapen
• at E14.5, embryos display severe midline defects and absence of many normal facial structures
• at E10.5, E11.5 and E12.5, all facial prominences are formed but the medial nasal prominences (MNP) and lateral nasal prominences (LNP) are severely reduced in size and underdeveloped
• at E18.5, all neural crest (NC)-derived bones are absent or reduced in size and misshapen, while paraxial mesoderm-derived parietal and interparietal bones are absent
• at E10.5, E11.5 and E12.5, the LNP are severely reduced in size and underdeveloped
• at E14.5, the LNP are of normal size but fail to undergo normal development
• at E14.5, maxillary prominences (MXP) are of normal size but fail to undergo normal development
• at E10.5, E11.5 and E12.5, the MNP are severely reduced in size and underdeveloped
• at E14.5, the MNP remain severely underdeveloped and are not merged with other facial elements
• palatal shelves fail to fuse along the midline even at E16.5
• palatal shelves are reduced in size
• at E14.5, the MNP are severely underdeveloped whereas the LNP and MXP are of normal size but fail to undergo normal development, resulting in an almost faceless phenotype, typical of much younger embryos
• after embryonic exposure to 150 mg/kg cyclopamine (an SHH signaling inhibitor), approximately one third of cyclopamine-treated embryos show a more normal looking face, with improved midfacial development, although the MNPs remain distinct
• at E14.5, palatal shelves are prematurely elevated above the tongue
• at E14.5, severe failure of midline fusion and loss of many facial structures are observed
• after embryonic exposure to 150 mg/kg cyclopamine (an SHH signaling inhibitor), approximately one third of cyclopamine-treated embryos show a partial rescue of the midline defects

growth/size/body
• palatal shelves fail to fuse along the midline even at E16.5
• palatal shelves are reduced in size
• at E14.5, the MNP are severely underdeveloped whereas the LNP and MXP are of normal size but fail to undergo normal development, resulting in an almost faceless phenotype, typical of much younger embryos
• after embryonic exposure to 150 mg/kg cyclopamine (an SHH signaling inhibitor), approximately one third of cyclopamine-treated embryos show a more normal looking face, with improved midfacial development, although the MNPs remain distinct
• at E14.5, palatal shelves are prematurely elevated above the tongue
• at E14.5, severe failure of midline fusion and loss of many facial structures are observed
• after embryonic exposure to 150 mg/kg cyclopamine (an SHH signaling inhibitor), approximately one third of cyclopamine-treated embryos show a partial rescue of the midline defects

reproductive system
• absent in 14 of 36 mice between E12.5 and E15.5
• remaining mice exhibit a range of defects including deformation, hypoplasia and proximal hypospadias

renal/urinary system
• in some mice

vision/eye
• embryos display hypertelorism at E14.5
• after embryonic exposure to 150 mg/kg cyclopamine (an SHH signaling inhibitor), approximately one third of cyclopamine-treated embryos show a partial rescue of the hypertelorism phenotype

digestive/alimentary system
• palatal shelves fail to fuse along the midline even at E16.5
• palatal shelves are reduced in size
• at E14.5, palatal shelves are prematurely elevated above the tongue


Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB)), Gene Ontology (GO)
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last database update
03/18/2025
MGI 6.24
The Jackson Laboratory